Oak trees susceptible to fungus

More and more people are hearing about oak wilt, but there are some facts worth repeating, and some things that have changed. For readers who haven’t heard about oak wilt, here are the basics: Oak wilt is a fungal disease that attacks all oaks, but red oaks are most susceptible and can die from the disease in as little as three weeks. (Red oaks are the oaks with points on the ends of their leaves.)

Oak wilt can spread in one of two ways. First, it can spread from tree to tree through root grafts. If the leaves of two red oaks are touching, there’s a good chance that their roots are connected too. Second, oak wilt can be spread by beetles attracted to the sap of injured trees. These beetles also feed on the fungal pads produced by the oak wilt fungus, so they can pick up the spores of the fungus and transfer it to a wounded but otherwise healthy tree.

The best way to keep your oak trees is to prevent infection in the first place. Even a nail can injure a tree enough to attract a beetle carrying oak wilt fungus, and larger injuries have greater risk. It is critical to avoid damage to oak trees while the sap is running, which means waiting until mid-October or later to prune oak trees.

If oak trees are damaged by accident or acts of nature in warmer months, use tree paint to cover the wound. If you are concerned about the health of an oak on your property or have questions, please contact the Conservation District Forester, Jocelyn Mahone, at 989.539.6401.